Evaluation of thermal destruction kinetics of Clostridium difficile spores (ATCC 17857) in lean ground beef with first-order/Weibull modeling considerations

Abstract

Thermal destruction kinetics of spores of Clostridium difficile ATCC 17857 was evaluated between 74 and 82°C and characterized using the first-order log-linear and Weibull models. Computed decimal reduction times using the first-order model ranged from 4.39 min at 82°C to 146 min at 74°C, with a z value of 5.17°C. Thermal destruction data were also analyzed using the Weibull model. Based on regression, the predicted one-D value (first-order model) and the reliable life (tR) (Weibull model) were 3.86 and 4.05 min at 82°C and 136 and 165 min at 74°C, respectively, indicating the Weibull model to be more conservative yielding higher decimal reduction time values. However, when extended to achieve 2.5, 4, and 6 decimal reductions in C. difficile spores, the calculated process times were more conservative with the first-order model than with the Weibull model. Moreover, within the experimental range, when data for both models could be compared, predictions from the first-order model were much closer to the experimental values. Therefore, when used for process calculation for 2.5 or higher log reductions, the first-order model would give more conservative and safer process times. The study provides destruction kinetics data for C. difficile under a range of temperature conditions.